1553. Infectious Complications Following Hematopoietic Cell Transplantation in Patients With Primary Immunodeficiency Diseases

BACKGROUND: Hematopoietic cell transplantation (HCT) has significantly improved long-term survival for children with primary immunodeficiency diseases (PID). Little is known about specific risk factors for infections after transplant in PID patients and differences from others undergoing HCT. Factors impacting success of HCT in PID include age at HCT, underlying genetic defect, type of donor and conditioning regimen, and importantly, the presence of pre-existing infection. We describe the epidemiology and risk factors for bacterial, viral and fungal infections in patients undergoing HCT for PID. METHODS: After IRB approval, medical records of patients undergoing HCT at Seattle Children’s Hospital for PID between 1998 and 2017 were reviewed. Donor and stem cell source, conditioning regimen, development of graft vs. host disease (GVHD), chimerism and mortality were considered, in addition to details of pre-HCT infections. Timing, character and treatment details of each incident infection during 12 months post-HCT were collected. Standardized antimicrobial prophylactic regimens were administered. Primary outcomes included mortality and infection-free survival. Kaplan–Meier curves were used to examine infection-free survival, by diagnosis and by HCT era. RESULTS: Sixty-nine patients with PID underwent HCT during the study period. Mean age at HCT was 6.2 years and varied by underlying PID. Altogether, 24 children (34.8%) had severe combined immune deficiency (SCID), 14 (20.3%) had chronic granulomatous disease (CGD), nine (13%) had combined immune deficiency (CID), and six (8.7%) had hyper IgM syndrome. Fifty-six patients received HLA-matched grafts. Umbilical cord blood was utilized in 10% of patients. Acute GVHD grades II–IV developed in 46 (67%) patients. Bacterial infections were the most common infection post-HCT, followed by respiratory and herpes group viral infections. Overall mortality at 1 year was 19%, of which at least 50% was infection related. CONCLUSION: Infection occurs frequently and contributes to morbidity and mortality in patients undergoing HCT for PID. Understanding the timing of infections and contributing risk factors could help develop preemptive and monitoring strategies to improve outcomes in this patient population. DISCLOSURES: All authors: No reported disclosures.